A continuous supply of hot steam is essential for the provision of many services in hotels, restaurants, hospitals and other public or private establishments. Hot steam is generally produced by boiling water under atmospheric pressure by directly heating a water vessel. Gas is widely used for generating hot steam. In conventional hot steam generating apparatuses using gas burners, a gas burner is placed underneath the bottom of a water vessel. Water contained in the vessel is heated by direct heating of the bottom of the water vessel by flames and heat generated by fuel gas combustion. In a conventional burner, the flames are pushed by gas pressure towards the bottom of the water vessel and spread over the bottom surface of the vessel, thereby heating the bottom surface of the vessel. However, conventional gas water steam generators are known to have relatively low thermal efficiency due to dissipation of the heat from the vessel into the atmosphere and also because the flame contact area only represents a small percentage of the combustion area. Typically, the thermal efficiency for conventional water steam generators or steam generators is below 80% for a large-size gas burner or for a heated water vessel with a flat vessel bottom.
The present invention recognizes and addresses disadvantages of prior art constructions and methods. Various combinations and sub-combinations of the disclosed elements, as well as methods of utilizing same, which are discussed in detail below, provide objects, features and aspects of the present invention.